Add croc code coverage tool. (Same change as yesterday, but now made in the...

tools/code_coverage/croc_test.py

+#!/usr/bin/python2.4
+#
+# Copyright 2009, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#        * Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#        * Redistributions in binary form must reproduce the above
+#     copyright notice, this list of conditions and the following disclaimer
+#     in the documentation and/or other materials provided with the
+#     distribution.
+#        * Neither the name of Google Inc. nor the names of its
+#     contributors may be used to endorse or promote products derived from
+#     this software without specific prior written permission.
+#
+#     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#     "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#     LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#     A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#     OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#     LIMITED TO, PROCUREMENT  OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#     DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#     THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#     OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Unit tests for Crocodile."""
+
+import os
+import re
+import sys
+import StringIO
+import unittest
+import croc
+
+#------------------------------------------------------------------------------
+
+class TestCoverageStats(unittest.TestCase):
+  """Tests for croc.CoverageStats."""
+
+  def testAdd(self):
+    """Test Add()."""
+    c = croc.CoverageStats()
+
+    # Initially empty
+    self.assertEqual(c, {})
+
+    # Add items
+    c['a'] = 1
+    c['b'] = 0
+    self.assertEqual(c, {'a':1, 'b':0})
+
+    # Add dict with non-overlapping items
+    c.Add({'c':5})
+    self.assertEqual(c, {'a':1, 'b':0, 'c':5})
+
+    # Add dict with overlapping items
+    c.Add({'a':4, 'd':3})
+    self.assertEqual(c, {'a':5, 'b':0, 'c':5, 'd':3})
+
+#------------------------------------------------------------------------------
+
+class TestCoveredFile(unittest.TestCase):
+  """Tests for croc.CoveredFile."""
+
+  def setUp(self):
+    self.cov_file = croc.CoveredFile('bob.cc', 'source', 'C++')
+
+  def testInit(self):
+    """Test init."""
+    f = self.cov_file
+
+    # Check initial values
+    self.assertEqual(f.filename, 'bob.cc')
+    self.assertEqual(f.group, 'source')
+    self.assertEqual(f.language, 'C++')
+    self.assertEqual(f.lines, {})
+    self.assertEqual(f.stats, {})
+
+  def testUpdateCoverageEmpty(self):
+    """Test updating coverage when empty."""
+    f = self.cov_file
+    f.UpdateCoverage()
+    self.assertEqual(f.stats, {
+        'lines_executable':0,
+        'lines_instrumented':0,
+        'lines_covered':0,
+        'files_executable':1,
+    })
+
+  def testUpdateCoverageExeOnly(self):
+    """Test updating coverage when no lines are instrumented."""
+    f = self.cov_file
+    f.lines = {1:None, 2:None, 4:None}
+    f.UpdateCoverage()
+    self.assertEqual(f.stats, {
+        'lines_executable':3,
+        'lines_instrumented':0,
+        'lines_covered':0,
+        'files_executable':1,
+    })
+
+  def testUpdateCoverageExeAndInstr(self):
+    """Test updating coverage when no lines are covered."""
+    f = self.cov_file
+    f.lines = {1:None, 2:None, 4:0, 5:0, 7:None}
+    f.UpdateCoverage()
+    self.assertEqual(f.stats, {
+        'lines_executable':5,
+        'lines_instrumented':2,
+        'lines_covered':0,
+        'files_executable':1,
+        'files_instrumented':1,
+    })
+
+  def testUpdateCoverageWhenCovered(self):
+    """Test updating coverage when lines are covered."""
+    f = self.cov_file
+    f.lines = {1:None, 2:None, 3:1, 4:0, 5:0, 6:1, 7:None}
+    f.UpdateCoverage()
+    self.assertEqual(f.stats, {
+        'lines_executable':7,
+        'lines_instrumented':4,
+        'lines_covered':2,
+        'files_executable':1,
+        'files_instrumented':1,
+        'files_covered':1,
+    })
+
+#------------------------------------------------------------------------------
+
+class TestCoveredDir(unittest.TestCase):
+  """Tests for croc.CoveredDir."""
+
+  def setUp(self):
+    self.cov_dir = croc.CoveredDir('/a/b/c')
+
+  def testInit(self):
+    """Test init."""
+    d = self.cov_dir
+
+    # Check initial values
+    self.assertEqual(d.dirpath, '/a/b/c')
+    self.assertEqual(d.files, {})
+    self.assertEqual(d.subdirs, {})
+    self.assertEqual(d.stats_by_group, {'all':{}})
+
+  def testGetTreeEmpty(self):
+    """Test getting empty tree."""
+    d = self.cov_dir
+    self.assertEqual(d.GetTree(), '/a/b/c/')
+
+  def testGetTreeStats(self):
+    """Test getting tree with stats."""
+    d = self.cov_dir
+    d.stats_by_group['all'] = croc.CoverageStats(
+        lines_executable=50, lines_instrumented=30, lines_covered=20)
+    d.stats_by_group['bar'] = croc.CoverageStats(
+        lines_executable=0, lines_instrumented=0, lines_covered=0)
+    d.stats_by_group['foo'] = croc.CoverageStats(
+        lines_executable=33, lines_instrumented=22, lines_covered=11)
+    # 'bar' group is skipped because it has no executable lines
+    self.assertEqual(d.GetTree(),
+        '/a/b/c/                          all:20/30/50   foo:11/22/33')
+
+  def testGetTreeSubdir(self):
+    """Test getting tree with subdirs."""
+    d1 = self.cov_dir = croc.CoveredDir('/a')
+    d2 = self.cov_dir = croc.CoveredDir('/a/b')
+    d3 = self.cov_dir = croc.CoveredDir('/a/c')
+    d4 = self.cov_dir = croc.CoveredDir('/a/b/d')
+    d5 = self.cov_dir = croc.CoveredDir('/a/b/e')
+    d1.subdirs = {'/a/b':d2, '/a/c':d3}
+    d2.subdirs = {'/a/b/d':d4, '/a/b/e':d5}
+    self.assertEqual(d1.GetTree(),
+                     '/a/\n  /a/b/\n    /a/b/d/\n    /a/b/e/\n  /a/c/')
+
+#------------------------------------------------------------------------------
+
+class TestCoverage(unittest.TestCase):
+  """Tests for croc.Coverage."""
+
+  def MockWalk(self, src_dir):
+    """Mock for os.walk().
+
+    Args:
+      src_dir: Source directory to walk.
+
+    Returns:
+      A list of (dirpath, dirnames, filenames) tuples.
+    """
+    self.mock_walk_calls.append(src_dir)
+    return self.mock_walk_return
+
+  def setUp(self):
+    """Per-test setup"""
+
+    # Empty coverage object
+    self.cov = croc.Coverage()
+
+    # Coverage object with minimal setup
+    self.cov_minimal = croc.Coverage()
+    self.cov_minimal.AddRoot('/src')
+    self.cov_minimal.AddRoot('c:\\source')
+    self.cov_minimal.AddRule('^#/', include=1, group='my')
+    self.cov_minimal.AddRule('.*\\.c$', language='C')
+    self.cov_minimal.AddRule('.*\\.c##$', language='C##') # sharper than thou
+
+    # Data for MockWalk()
+    self.mock_walk_calls = []
+    self.mock_walk_return = []
+
+  def testInit(self):
+    """Test init."""
+    c = self.cov
+    self.assertEqual(c.files, {})
+    self.assertEqual(c.root_dirs, [])
+    self.assertEqual(c.print_stats, [])
+
+    # Check for the initial subdir rule
+    self.assertEqual(len(c.rules), 1)
+    r0 = c.rules[0]
+    self.assertEqual(r0[0].pattern, '.*/$')
+    self.assertEqual(r0[1:], [None, None, 'subdir'])
+
+  def testAddRoot(self):
+    """Test AddRoot() and CleanupFilename()."""
+    c = self.cov
+
+    # Check for identity on already-clean filenames
+    self.assertEqual(c.CleanupFilename(''), '')
+    self.assertEqual(c.CleanupFilename('a'), 'a')
+    self.assertEqual(c.CleanupFilename('.a'), '.a')
+    self.assertEqual(c.CleanupFilename('..a'), '..a')
+    self.assertEqual(c.CleanupFilename('a.b'), 'a.b')
+    self.assertEqual(c.CleanupFilename('a/b/c'), 'a/b/c')
+    self.assertEqual(c.CleanupFilename('a/b/c/'), 'a/b/c/')
+
+    # Backslash to forward slash
+    self.assertEqual(c.CleanupFilename('a\\b\\c'), 'a/b/c')
+
+    # Handle relative paths
+    self.assertEqual(c.CleanupFilename('.'),
+                     c.CleanupFilename(os.path.abspath('.')))
+    self.assertEqual(c.CleanupFilename('..'),
+                     c.CleanupFilename(os.path.abspath('..')))
+    self.assertEqual(c.CleanupFilename('./foo/bar'),
+                     c.CleanupFilename(os.path.abspath('./foo/bar')))
+    self.assertEqual(c.CleanupFilename('../../a/b/c'),
+                     c.CleanupFilename(os.path.abspath('../../a/b/c')))
+
+    # Replace alt roots
+    c.AddRoot('foo', '#')
+    self.assertEqual(c.CleanupFilename('foo'), '#')
+    self.assertEqual(c.CleanupFilename('foo/bar/baz'), '#/bar/baz')
+    self.assertEqual(c.CleanupFilename('aaa/foo'), 'aaa/foo')
+
+    # Alt root replacement is applied for all roots
+    c.AddRoot('foo/bar', '#B')
+    self.assertEqual(c.CleanupFilename('foo/bar/baz'), '#B/baz')
+
+    # Can use previously defined roots in cleanup
+    c.AddRoot('#/nom/nom/nom', '#CANHAS')
+    self.assertEqual(c.CleanupFilename('foo/nom/nom/nom/cheezburger'),
+                     '#CANHAS/cheezburger')
+
+    # Verify roots starting with UNC paths or drive letters work, and that
+    # more than one root can point to the same alt_name
+    c.AddRoot('/usr/local/foo', '#FOO')
+    c.AddRoot('D:\\my\\foo', '#FOO')
+    self.assertEqual(c.CleanupFilename('/usr/local/foo/a/b'), '#FOO/a/b')
+    self.assertEqual(c.CleanupFilename('D:\\my\\foo\\c\\d'), '#FOO/c/d')
+
+  def testAddRule(self):
+    """Test AddRule() and ClassifyFile()."""
+    c = self.cov
+
+    # With only the default rule, nothing gets kept
+    self.assertEqual(c.ClassifyFile('#/src/'), (None, None))
+    self.assertEqual(c.ClassifyFile('#/src/a.c'), (None, None))
+
+    # Add rules to include a tree and set a default group
+    c.AddRule('^#/src/', include=1, group='source')
+    # Now the subdir matches, but source doesn't, since no languages are
+    # defined yet
+    self.assertEqual(c.ClassifyFile('#/src/'), ('source', 'subdir'))
+    self.assertEqual(c.ClassifyFile('#/notsrc/'), (None, None))
+    self.assertEqual(c.ClassifyFile('#/src/a.c'), (None, None))
+
+    # Define some languages and groups
+    c.AddRule('.*\\.(c|h)$', language='C')
+    c.AddRule('.*\\.py$', language='Python')
+    c.AddRule('.*_test\\.', group='test')
+    self.assertEqual(c.ClassifyFile('#/src/a.c'), ('source', 'C'))
+    self.assertEqual(c.ClassifyFile('#/src/a.h'), ('source', 'C'))
+    self.assertEqual(c.ClassifyFile('#/src/a.cpp'), (None, None))
+    self.assertEqual(c.ClassifyFile('#/src/a_test.c'), ('test', 'C'))
+    self.assertEqual(c.ClassifyFile('#/src/test_a.c'), ('source', 'C'))
+    self.assertEqual(c.ClassifyFile('#/src/foo/bar.py'), ('source', 'Python'))
+    self.assertEqual(c.ClassifyFile('#/src/test.py'), ('source', 'Python'))
+
+    # Exclude a path (for example, anything in a build output dir)
+    c.AddRule('.*/build/', include=0)
+    # But add back in a dir which matched the above rule but isn't a build
+    # output dir
+    c.AddRule('#/src/tools/build/', include=1)
+    self.assertEqual(c.ClassifyFile('#/src/build.c'), ('source', 'C'))
+    self.assertEqual(c.ClassifyFile('#/src/build/'), (None, None))
+    self.assertEqual(c.ClassifyFile('#/src/build/a.c'), (None, None))
+    self.assertEqual(c.ClassifyFile('#/src/tools/build/'), ('source', 'subdir'))
+    self.assertEqual(c.ClassifyFile('#/src/tools/build/t.c'), ('source', 'C'))
+
+  def testGetCoveredFile(self):
+    """Test GetCoveredFile()."""
+    c = self.cov_minimal
+
+    # Not currently any covered files
+    self.assertEqual(c.GetCoveredFile('#/a.c'), None)
+
+    # Add some files
+    a_c = c.GetCoveredFile('#/a.c', add=True)
+    b_c = c.GetCoveredFile('#/b.c##', add=True)
+    self.assertEqual(a_c.filename, '#/a.c')
+    self.assertEqual(a_c.group, 'my')
+    self.assertEqual(a_c.language, 'C')
+    self.assertEqual(b_c.filename, '#/b.c##')
+    self.assertEqual(b_c.group, 'my')
+    self.assertEqual(b_c.language, 'C##')
+
+    # Specifying the same filename should return the existing object
+    self.assertEqual(c.GetCoveredFile('#/a.c'), a_c)
+    self.assertEqual(c.GetCoveredFile('#/a.c', add=True), a_c)
+
+    # Filenames get cleaned on the way in, as do root paths
+    self.assertEqual(c.GetCoveredFile('/src/a.c'), a_c)
+    self.assertEqual(c.GetCoveredFile('c:\\source\\a.c'), a_c)
+
+  def testParseLcov(self):
+    """Test ParseLcovData()."""
+    c = self.cov_minimal
+
+    c.ParseLcovData([
+        '# Ignore unknown lines',
+        # File we should include'
+        'SF:/src/a.c',
+        'DA:10,1',
+        'DA:11,0',
+        'DA:12,1   \n', # Trailing whitespace should get stripped
+        'end_of_record',
+        # File we should ignore
+        'SF:/not_src/a.c',
+        'DA:20,1',
+        'end_of_record',
+        # Same as first source file, but alternate root
+        'SF:c:\\source\\a.c',
+        'DA:30,1',
+        'end_of_record',
+        # Ignore extra end of record
+        'end_of_record',
+        # Ignore data points after end of record
+        'DA:40,1',
+        # Instrumented but uncovered file
+        'SF:/src/b.c',
+        'DA:50,0',
+        'end_of_record',
+    ])
+
+    # We should know about two files
+    self.assertEqual(sorted(c.files), ['#/a.c', '#/b.c'])
+
+    # Check expected contents
+    a_c = c.GetCoveredFile('#/a.c')
+    self.assertEqual(a_c.lines, {10: 1, 11: 0, 12: 1, 30: 1})
+    self.assertEqual(a_c.stats, {
+        'files_executable': 1,
+        'files_instrumented': 1,
+        'files_covered': 1,
+        'lines_instrumented': 4,
+        'lines_executable': 4,
+        'lines_covered': 3,
+    })
+    b_c = c.GetCoveredFile('#/b.c')
+    self.assertEqual(b_c.lines, {50: 0})
+    self.assertEqual(b_c.stats, {
+        'files_executable': 1,
+        'files_instrumented': 1,
+        'lines_instrumented': 1,
+        'lines_executable': 1,
+        'lines_covered': 0,
+    })
+
+  def testGetStat(self):
+    """Test GetStat() and PrintStat()."""
+    c = self.cov
+
+    # Add some stats, so there's something to report
+    c.tree.stats_by_group = {
+        'all': {
+            'count_a': 10,
+            'count_b': 4,
+            'foo': 'bar',
+        },
+        'tests': {
+            'count_a': 2,
+            'count_b': 5,
+            'baz': 'bob',
+        },
+    }
+
+    # Test missing stats and groups
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'nosuch')
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'baz')
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'foo', group='tests')
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'foo', group='nosuch')
+
+    # Test returning defaults
+    self.assertEqual(c.GetStat('nosuch', default=13), 13)
+    self.assertEqual(c.GetStat('baz', default='aaa'), 'aaa')
+    self.assertEqual(c.GetStat('foo', group='tests', default=0), 0)
+    self.assertEqual(c.GetStat('foo', group='nosuch', default=''), '')
+
+    # Test getting stats
+    self.assertEqual(c.GetStat('count_a'), 10)
+    self.assertEqual(c.GetStat('count_a', group='tests'), 2)
+    self.assertEqual(c.GetStat('foo', default='baz'), 'bar')
+
+    # Test stat math (eval)
+    self.assertEqual(c.GetStat('count_a - count_b'), 6)
+    self.assertEqual(c.GetStat('100.0 * count_a / count_b', group='tests'),
+                     40.0)
+    # Should catch eval errors
+    self.assertRaises(croc.CoverageStatError, c.GetStat, '100 / 0')
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'count_a -')
+
+    # Test nested stats via S()
+    self.assertEqual(c.GetStat('count_a - S("count_a", group="tests")'), 8)
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'S()')
+    self.assertRaises(croc.CoverageStatError, c.GetStat, 'S("nosuch")')
+
+    # Test PrintStat()
+    # We won't see the first print, but at least verify it doesn't assert
+    c.PrintStat('count_a', format='(test to stdout: %s)')
+    # Send subsequent prints to a file
+    f = StringIO.StringIO()
+    c.PrintStat('count_b', outfile=f)
+    # Test specifying output format
+    c.PrintStat('count_a', format='Count A = %05d', outfile=f)
+    # Test specifing additional keyword args
+    c.PrintStat('count_a', group='tests', outfile=f)
+    c.PrintStat('nosuch', default=42, outfile=f)
+    self.assertEqual(f.getvalue(), ("""\
+GetStat('count_b') = 4
+Count A = 00010
+GetStat('count_a') = 2
+GetStat('nosuch') = 42
+"""))
+    f.close()
+
+  def testAddConfigEmpty(self):
+    """Test AddConfig() with empty config."""
+    c = self.cov
+    # Most minimal config is an empty dict; should do nothing
+    c.AddConfig('{} # And we ignore comments')
+
+  def testAddConfig(self):
+    """Test AddConfig()."""
+    c = self.cov
+    lcov_queue = []
+    addfiles_queue = []
+
+    c.AddConfig("""{
+        'roots' : [
+          {'root' : '/foo'},
+          {'root' : '/bar', 'altname' : '#BAR'},
+        ],
+        'rules' : [
+          {'regexp' : '^#', 'group' : 'apple'},
+          {'regexp' : 're2', 'include' : 1, 'language' : 'elvish'},
+        ],
+        'lcov_files' : ['a.lcov', 'b.lcov'],
+        'add_files' : ['/src', '#BAR/doo'],
+        'print_stats' : [
+          {'stat' : 'count_a'},
+          {'stat' : 'count_b', 'group' : 'tests'},
+        ],
+        'extra_key' : 'is ignored',
+    }""", lcov_queue=lcov_queue, addfiles_queue=addfiles_queue)
+
+    self.assertEqual(lcov_queue, ['a.lcov', 'b.lcov'])
+    self.assertEqual(addfiles_queue, ['/src', '#BAR/doo'])
+    self.assertEqual(c.root_dirs, [['/foo', '#'], ['/bar', '#BAR']])
+    self.assertEqual(c.print_stats, [
+        {'stat': 'count_a'},
+        {'stat': 'count_b', 'group': 'tests'},
+    ])
+    # Convert compiled re's back to patterns for comparison
+    rules = [[r[0].pattern] + r[1:] for r in c.rules]
+    self.assertEqual(rules, [
+        ['.*/$', None, None, 'subdir'],
+        ['^#', None, 'apple', None],
+        ['re2', 1, None, 'elvish'],
+    ])
+
+  def testAddFilesSimple(self):
+    """Test AddFiles() simple call."""
+    c = self.cov_minimal
+    c.add_files_walk = self.MockWalk
+    c.AddFiles('/a/b/c')
+    self.assertEqual(self.mock_walk_calls, ['/a/b/c'])
+    self.assertEqual(c.files, {})
+
+  def testAddFilesRootMap(self):
+    """Test AddFiles() with root mappings."""
+    c = self.cov_minimal
+    c.add_files_walk = self.MockWalk
+    c.AddRoot('#/subdir', '#SUBDIR')
+
+    # AddFiles() should replace the '#SUBDIR' alt_name, then match both
+    # possible roots for the '#' alt_name.
+    c.AddFiles('#SUBDIR/foo')
+    self.assertEqual(self.mock_walk_calls,
+                     ['/src/subdir/foo', 'c:/source/subdir/foo'])
+    self.assertEqual(c.files, {})
+
+  def testAddFilesNonEmpty(self):
+    """Test AddFiles() where files are returned."""
+
+    c = self.cov_minimal
+    c.add_files_walk = self.MockWalk
+
+    # Add a rule to exclude a subdir
+    c.AddRule('^#/proj1/excluded/', include=0)
+
+    # Set data for mock walk
+    self.mock_walk_return = [
+        [
+            '/src/proj1',
+            ['excluded', 'subdir'],
+            ['a.c', 'no.f', 'yes.c'],
+        ],
+        [
+            '/src/proj1/subdir',
+            [],
+            ['cherry.c'],
+        ],
+    ]
+
+    c.AddFiles('/src/proj1')
+
+    self.assertEqual(self.mock_walk_calls, ['/src/proj1'])
+
+    # Include files from the main dir and subdir
+    self.assertEqual(sorted(c.files), [
+        '#/proj1/a.c',
+        '#/proj1/subdir/cherry.c',
+        '#/proj1/yes.c'])
+
+    # Excluded dir should have been pruned from the mock walk data dirnames.
+    # In the real os.walk() call this prunes the walk.
+    self.assertEqual(self.mock_walk_return[0][1], ['subdir'])
+
+  def testUpdateTreeStats(self):
+    """Test UpdateTreeStats()."""
+
+    c = self.cov_minimal
+
+
+
+    c.AddRule('.*_test', group='test')
+
+    # Fill the files list
+    c.ParseLcovData([
+        'SF:/src/a.c',
+        'DA:10,1', 'DA:11,1', 'DA:20,0',
+        'end_of_record',
+        'SF:/src/a_test.c',
+        'DA:10,1', 'DA:11,1', 'DA:12,1',
+        'end_of_record',
+        'SF:/src/foo/b.c',
+        'DA:10,1', 'DA:11,1', 'DA:20,0', 'DA:21,0', 'DA:30,0',
+        'end_of_record',
+        'SF:/src/foo/b_test.c',
+        'DA:20,0', 'DA:21,0', 'DA:22,0',
+        'end_of_record',
+    ])
+    c.UpdateTreeStats()
+
+    t = c.tree
+    self.assertEqual(t.dirpath, '')
+    self.assertEqual(sorted(t.files), [])
+    self.assertEqual(sorted(t.subdirs), ['#'])
+    self.assertEqual(t.stats_by_group, {
+        'all': {
+            'files_covered': 3,
+            'files_executable': 4,
+            'lines_executable': 14,
+            'lines_covered': 7,
+            'lines_instrumented': 14,
+            'files_instrumented': 4,
+        },
+        'my': {
+            'files_covered': 2,
+            'files_executable': 2,
+            'lines_executable': 8,
+            'lines_covered': 4,
+            'lines_instrumented': 8,
+            'files_instrumented': 2,
+        },
+        'test': {
+            'files_covered': 1,
+            'files_executable': 2,
+            'lines_executable': 6,
+            'lines_covered': 3,
+            'lines_instrumented': 6,
+            'files_instrumented': 2,
+        },
+    })
+
+    t = t.subdirs['#']
+    self.assertEqual(t.dirpath, '#')
+    self.assertEqual(sorted(t.files), ['a.c', 'a_test.c'])
+    self.assertEqual(sorted(t.subdirs), ['foo'])
+    self.assertEqual(t.stats_by_group, {
+        'all': {
+            'files_covered': 3,
+            'files_executable': 4,
+            'lines_executable': 14,
+            'lines_covered': 7,
+            'lines_instrumented': 14,
+            'files_instrumented': 4,
+        },
+        'my': {
+            'files_covered': 2,
+            'files_executable': 2,
+            'lines_executable': 8,
+            'lines_covered': 4,
+            'lines_instrumented': 8,
+            'files_instrumented': 2,
+        },
+        'test': {
+            'files_covered': 1,
+            'files_executable': 2,
+            'lines_executable': 6,
+            'lines_covered': 3,
+            'lines_instrumented': 6,
+            'files_instrumented': 2,
+        },
+    })
+
+    t = t.subdirs['foo']
+    self.assertEqual(t.dirpath, 'foo')
+    self.assertEqual(sorted(t.files), ['b.c', 'b_test.c'])
+    self.assertEqual(sorted(t.subdirs), [])
+    self.assertEqual(t.stats_by_group, {
+        'test': {
+            'files_executable': 1,
+            'files_instrumented': 1,
+            'lines_executable': 3,
+            'lines_instrumented': 3,
+            'lines_covered': 0,
+        },
+        'all': {
+            'files_covered': 1,
+            'files_executable': 2,
+            'lines_executable': 8,
+            'lines_covered': 2,
+            'lines_instrumented': 8,
+            'files_instrumented': 2,
+        },
+        'my': {
+            'files_covered': 1,
+            'files_executable': 1,
+            'lines_executable': 5,
+            'lines_covered': 2,
+            'lines_instrumented': 5,
+            'files_instrumented': 1,
+        }
+    })
+
+  # TODO: test: less important, since these are thin wrappers around other
+  # tested methods.
+  #     ParseConfig()
+  #     ParseLcovFile()
+  #     PrintTree()
+
+#------------------------------------------------------------------------------
+
+if __name__ == '__main__':
+  unittest.main()